Senior Blockchain Engineer - Backend, Fanatics Markets in London

Fanatics Markets is the real-money prediction and trading app where you can invest in moments you care about. Built on a secure platform, we let users predict real-world outcomes and trade on events they actually follow - from sports and entertainment to political elections and beyond. Our mission is to redefine how fans engage with the moments and markets that matter most. We are looking for the right people to help us build the future of prediction markets.

This Software Engineer III (Backend) role is a senior-level IC with significant ownership over the web application that customers use to interact with our product. You will join a true 0→1 team, helping define the product, technical foundations, and ways of working from scratch. You will lead by example, establishing best practices for AI-assisted development while building systems that can handle millions of events daily.

On the engineering side, we are pioneering the use of AI as a code collaborator. We need engineers who have gone beyond experimentation—who actively use Claude Code, Cursor, Codex, GitHub Copilot, or similar tools to ship production code faster while maintaining exceptional quality standards.

• Lead the design, development, testing, and deployment of scalable, high-quality backend services in Go.
• Drive the technical evolution of our markets and trading backend, partnering with product and other engineering teams to deliver robust, observable, and maintainable systems.
• Own services and features end-to-end: spec writing → implementation → instrumentation → deployment → monitoring → iteration based on metrics.
• Design and implement experimentation capabilities (feature flags, A/B tests) to validate ideas quickly and safely.
• Model and manage data for markets, orders, and transactions with a focus on correctness, integrity, and auditability.
• Integrate on-chain and off-chain data sources, building reliable pipelines for blockchain event ingestion and querying.
• Collaborate on reliability practices including on-call participation, SLO definition, alerting, and incident response.
• Conduct thorough code reviews, raising the bar on code quality, readability, and maintainability.
• Leverage AI tools to accelerate development velocity while maintaining high standards for security, correctness, and performance.
• Establish and document team standards for AI usage (prompt patterns, code review checklists, validation strategies).
• Contribute to a fast-paced 0→1 environment, unblocking others and taking initiative where processes are still being defined.

• 4+ years of experience building highly scalable, high-performance backend applications or distributed systems.
• Hands-on experience building blockchain dApps or services integrating with EVM or Solana (hackathons, side projects, or production work all count).
• Experience querying and integrating blockchain data (e.g., event logs, indexing, reconciliation between on-chain and off-chain state).
• Experience with PostgreSQL - complex query optimization, indexing strategies, and schema/migration management.
• Experience with event-driven architecture like Kafka or PubSub.
• Strong grasp of software design principles (e.g., SOLID, DRY) and testing methodologies (unit, integration, and end-to-end testing).
• Experience designing and integrating backend APIs and collaborating with cross-functional platform and product teams.
• Familiarity with CI/CD pipelines, automated testing, and safe deployment strategies for backend services.
• Experience working with production reliability practices (monitoring, logging, alerting, and basic SLO concepts).
• Demonstrated experience using AI tools (Claude Code, Cursor, Copilot, etc.) to ship production code.
• Can demonstrate specific examples of workflow improvements from AI-assisted development (e.g., "reduced boilerplate generation time by 40%").
• Effectively communicates complex technical concepts clearly to diverse audiences, including engineers and stakeholders.
• Thrives in a high-growth environment where priorities evolve regularly and decisions are made quickly.
• Strong ability to collaborate cross-functionally across diverse teams within large enterprise environments, while operating with a startup mindset.

• Experience using Go in production environments.
• Previous experience in 0→1 or high-growth startup environments.
• Contributions to open-source projects or technical community.
• Experience with real-money transaction systems and regulatory compliance.
• Background in building developer tools or improving engineering productivity.
• Experience leading without authority and influencing technical direction across teams.

Depending on the role, your interview and onboarding experience may include in-person components, such as onsite interviews or Launching into Better: LIVE—a multi-day cultural immersion in New York City for full-time, non-seasonal hires. These sessions are designed to build connection and bring our culture to life, though specific travel and participation requirements will be confirmed based on your role and location. Your recruiter will provide clear guidance at each stage of the process.

Ready to build the future of sports betting? If you possess some of these skills but not all of them, we still encourage you to apply!

Please note that visa sponsorship is not available for this position. We are open to fully remote candidates based in the United Kingdom. Remote employees may also be eligible for a home office setup stipend.